Sulcal Hyperintensity as an Early Imaging Finding in Cerebral Amyloid Angiopathy-Related Inflammation

Abstract

Background and objectives: Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a subtype of CAA with distinct clinical and radiologic features. Existing diagnostic criteria require the presence of characteristic asymmetrical white matter hyperintensity (WMH), together with classical hemorrhagic neuroimaging markers of CAA. There are limited data for other diagnostic neuroimaging markers of CAA-ri.

Methods: This is a case series from a specialist hospital intracerebral hemorrhage service.

Results: We describe 4 patients with CAA-ri who had regions of sulcal hyperintensity, with or without gyral swelling at clinical presentation, but did not fulfill current diagnostic criteria because of the absence of typical asymmetric WMH on brain MRI. All 4 patients were subsequently diagnosed with CAA-ri; three later developed asymmetric WMHs with disease relapse, and 2 had pathologically proven CAA-ri; 1 patient had both.

Discussion: Regions of sulcal hyperintensity, sometimes with associated gyral swelling, can be an early imaging finding in CAA-ri. These neuroimaging markers could potentially improve the accuracy of existing diagnostic criteria for CAA-ri to allow earlier diagnosis and treatment without biopsy in patients with atypical presentations.

Figure 1. Representative MRI Findings for the Cases Described

Case 1 (A–D): MRI at initial presentation showed sulcal hyperintensity (SH) on fluid attenuated inversion recovery (FLAIR) images (A), leptomeningeal contrast enhancement (B, red arrowheads); MRI at relapse 5 months after initial presentation showed asymmetric white matter hyperintensity (WMH), over the left parietal and occipital lobes (C), in addition to multiple cortical and subcortical foci of restricted diffusion on DWI sequences (D). Case 2 (E–H): MRI at presentation showed SH over the left frontal lobe on FLAIR images (E), leptomeningeal contrast enhancement (F, red arrowheads), lobar cerebral microbleeds (CMB, red arrowheads), and areas of cortical superficial siderosis (cSS), mostly over the left frontal lobe on SWI (G), and multiple subcortical DWI lesions (H). Case 3 (I–L): MRI at initial presentation showed a subtle area of cortical swelling and SH in the left parietal region (I, red arrowhead); MRI at relapse showed a new patch of the WMH in the left temporoparietal region (J), associated with a cluster of CMB (K). The follow-up image 2 years later showed leptomeningeal enhancement in the left temporoparietal region (L, red arrowhead). Case 4 (M–P): MRI at initial presentation showed SH with gyral swelling on the FLAIR image over the right frontal lobe and occipital lobes bilaterally (M); MRI at relapse 9 months later showed areas of WMH with mild parenchymal swelling on T2 (N) and FLAIR (O) images primarily affecting the left perirolandic region, and leptomeningeal contrast enhancement (P, red arrowheads).